function openNav() {
    document.getElementById("menu").style.width="18%";
    document.getElementById("content").style.width="82%";
    document.getElementsByClassName("menu_button")[0].style.display="none";
}
function  closeNav() {
    document.getElementById("menu").style.width="0";
    document.getElementById("content").style.width="100%";
    document.getElementsByClassName("menu_button")[0].style.display="block";
}
function show(index) {
    var a = parseInt(document.getElementsByClassName("item")[index].value);
    document.getElementsByClassName("item")[index].value = (a + 1) % 2;
    if (a == 1) {
        document.getElementsByClassName("two")[index].style.display = "block";
    } else {
        document.getElementsByClassName("two")[index].style.display = "none";
    }
}
